Gas Hydrates: the Gent debates. Outlook on research horizons
and strategies
J.-P. HENRIET1 & J. MIENERT2
l
Renard Centre of Marine Geology, Geological Institute, University of Gent,
Krijgslaan 281-S8, B-9000 Gent, Belgium
2
GEOMAR, Research Centre for Marine Geosciences, Wischhofstr. 1-3, D24148 Kiel,
Germany
In 1811 Sir Humphry Davy, who gained fame for
both his research on the methane-laden atmospheres in British coal mines and his synthesis
of various new elements and compounds, witnessed the first chlorine hydrate crystallizing.
At that time he probably did not imagine that
185 years later methane hydrates would fuel
heated debates under the gothic vaults of a
former Dominican monastery in Gent.
Natural gas hydrates have come a long way.
From a mere chemical curiosity they proved, as
early as the mid-1930s, to be a nuisance for the
natural gas industry. Its impact increased in the
1970s, with even the largest pipelines from offshore or arctic fields or the wells from high-pressure underground storage facilities becoming
clogged by hydrate plugs. As todays hydrocarbon industry makes a strategic move towards
the continental slope, oceanic gas hydrates are
increasingly recognized as a major potential
hazard for the stability of offshore structures in
various deep-water hydrocarbon provinces.
Beyond these direct interferences with man's
industrial ventures, gas hydrates are gradually
moving onto the foreground of global climate
debates. If present estimates of methane hydrate
volumes stored in the oceanic margin sediments
are substantiated, natural gas hydrates represent,
under the present climatic and oceanographic
conditions, by far the largest mass of organic
carbon stored in a potentially dynamic reservoir
of the globe's carbon cycle. Their stability is controlled to a large extent by the temperature
regime of the oceans and by pressure conditions
on the seabed, both of which are directly linked
to sea-level changes.
This vast quantity of 'frozen' greenhouse gas
may have played a significant role in the global
symphony of ice ages and the dramatic climatic
shifts which characterize the Late Cenozoic
world. And it may still play a role today, perhaps
hardly noticed against the background of the
present world's CO2-driven climate machine.
But we cannot exclude the possibility that any
major modification of the ocean's dynamic ther-
mal structure in a warming world might unleash
vast amounts of methane from its seabed reservoir. Such a release would potentially contribute
to the already anticipated evolution of the
Earth's atmosphere, with methane at sometime
in the foreseeable future replacing carbon dioxide in its prime role as a global warming agent.
Is such a scenario possible, even plausible?
Can we quantify it and introduce it into our
models? Does it imply a fundamental change in
our modelling approaches, and should the now
familiar coupled ocean-atmosphere models
give way to coupled seabed-ocean-atmosphere
models? Can the estimates of the scale of the
hydrate reservoir be substantiated by any
ground-truthing? How can the mechanisms of
mass and energy transfer between the seabed,
ocean and atmosphere, linked to hydrate
growth and decay, be unravelled and quantified?
And which strategy should be adopted for
achieving such ambitious goals?
This profusion of questions, in the first
instance, calls for dialogue and concerted efforts
between various disciplines, from geophysics and
geochemistry to ocean and atmospheric physics
and chemistry, sedimentology, thermodynamics,
ice core stratigraphy, biogeochemistry and many
more fields of research. The questions prompt
immediate dialogue between academic and
industrial partners and call for sustained, longterm efforts, focused in their objectives but
global in their relevance.
Such questions were also the subject of the
workshop 'Gas hydrates: relevance to world
margin stability and climatic change', organized
in Gent in September 1996 under the auspices
of the European Commission's Marine Science
and Technology (MAST) Programme and the
European Marine and Polar Science Boards
(EMaPS).
This eminent patronage occurred because of
the outstanding fundamental scientific relevance
of this topic, which truly blends with far-reaching
economical and societal considerations, and
because the northwest European continental
HENRIET, J.-P. & MIENERT, J. 1998. Gas hydrates: the Gent debates. Outlook on research horizons and strategies.
In: HENRIET, J.-P. & MIENERT, J. (eds) Gas Hydrates: Relevance to World Margin Stability and Climate Change.
Geological Society, London, Special Publications, 137, 1-8.
2
J.-P. HENRIET & J. MIENERT
margin, Europe's new frontier for hydrocarbon
resources, turns out to be a vast natural laboratory for the interaction between gas hydrates
and slope stabilities, where some of the world's
largest submarine slides have yet to be studied
with advanced research. This is exactly the type
of natural European laboratory which has the
potential to lead to fundamental breakthroughs
of global relevance.
With such outstanding natural laboratories
along Europe's margins, research will transgress
the European scientific and human dimensions.
The interaction between oceanic conditions and
the seabed along the North Atlantic margins is
a basin-wide scientific challenge that calls for
organization and, wherever possible, cooperation with U.S. and Canadian partners. On Europe's northern frontier, in the Arctic seas, and
on its southern flank, in the eastern Mediterranean and Black Sea, hydrate research has been
pioneered by Russian institutes, which are
becoming Europe's active partners. Last but
not least, Europe should not overlook the important momentum in fundamental and applied
hydrate research in the Far East, particularly at
Japanese institutes.
This volume draws on state-of-the-art hydrate
research information from leading scientists,
from the USA, Russia and the European
Union. Kvenvolden (US Geological Survey in
Menlo Park) and Sloan (Colorado School of
Mines) set the stage for the volume. Both take
the reader on a journey from the fundamentals
of oceanic hydrates, or clathrates, to their
vision of the relevance of hydrates as an energy
resource, as a factor of margin stability and of
climatic change. This journey benefits from
both the affinities and the differences in perspective of both authors, partly due to the different
'cultural' environments from which they come.
Kvenvolden builds upon USGS databases to
highlight the geological occurrence and the
resource dimension of gas hydrates in a global
context, while Sloan utilizes his laboratory
studies to introduce the reader to the fundamental physical and chemical properties of gas
hydrates, their characterization and kinetics of
formation and decay. The latter contribution
sets the stage for the following chapter, which
addresses some fundamental insights into
hydrate generation and identifies challenges in
modelling.
The following sections of this introductory
paper summarize the outcomes of the round
table debates which animated the Gent workshop, and introduce papers in this volume. It
should be emphasized that where present-day
forums on oceanic gas hydrates research cur-
rently encompass the trilogy 'resource-hazardclimate issue', as introduced by Kvenvolden
and Sloan, the Gent workshop deliberately
focused on slope stability and climatic issues.
The contents and structure of this Special Publication reflect this focus.
The first round table discussion of the workshop focused on the challenges ahead in understanding the generation of oceanic gas hydrates
and in assessing the physics and chemistry of
oceanic hydrate-bearing sediments. Contributors
to the discussion were Ben Clennell and Gabriel
Ginsburg (panel members), Myriam Kastner
(moderator), Hans Amann, Bill Dillon, Bilal
Haq, Jean-Pierre Henriet, James Kennett,
Keith Kvenvolden, Dave Long, Charles Paull,
Carolyn Ruppel, Alister Skinner, Dendy Sloan,
Tjeerd Van Weering and Warren Wood.
Analysis and modelling of hydrate formation
A prime question emerging from the debate is
how we actually view the hydrate zone as a complex, multiphase system and in particular how we
view multiphase fluid transport and hydrate generation in porous media. There are still vast
opportunities offered to hydrate research to
draw upon the extensive literature in related
fields such as chemical engineering (chemical
reactors) and various fields of civil engineering,
and to design suitably controlled experiments.
An important issue is the residence time of gas
within the hydrate stability zone. Only a minor
portion of the gas migrating through a hydrate
stability zone seems to be actually trapped in
hydrates. The kinetics of such entrapment
needs clarification. However, it is clear that the
host sediments are not merely behaving as a passive matrix in which hydrates accumulate. Surface forces on mineral particles may control the
kinetics of hydrate formation and the stability
of hydrates in the sediment pores. And it is the
grain size which is likely to control the spatial
distribution of hydrates: in coarse sediments,
gas hydrates are often found to cement the
grains throughout the matrix, whereas in finer
sediments they frequently occur as discrete
nodules, sheets or lenses.
Ginsburg focuses on the spatial variability of
gas solubility in pore waters, and highlights the
inhomogeneous distribution of hydrates within
the hydrate stability zone. Rempel & Buffett venture to construct relatively simple models that
quantitatively predict the development of
hydrate layers, both for advection of gas from
deeper reservoirs and for in situ biogenic production. The latter model meets Ginsburg's observa-
GAS HYDRATES: THE GENT DEBATES
tion about a shallow region with elevated hydrate
saturation. Natural gas hydrates however do not
have a simple composition: they are solid solutions of water and a variety of gases such as
CO2, CH4, N2 and C2H6, and may contain significant concentrations of H2S. Bakker develops
and models stability conditions for fluid systems
and gas clathrates with a complex composition,
thoroughly testing them against experimental
data. Lu & Matsumoto focus on the formation
of CO2 hydrates under varying pH conditions.
Exploration strategy and field evaluation
methodology
The habitat of hydrates in sediments will control
their geophysical response, whether electrical,
seismic or thermal. The calibration of geophysical responses will require extensive ground-truthing through drilling and the recovery of
undisturbed samples for analysis in the laboratory under the original ambient pressure. This
calls for the development of a new generation
of pressure core samplers and core logging
devices, as well as instruments allowing imaging
(NMR imaging, CAT-scanning) and controlled
experiments inside pressurized cores. Only this
type of approach will allow the proper calibration of downhole logging responses.
Booth et al. introduce a comprehensive first
overview of the spatial distribution of hydrates
in various 'reservoirs' and environments, as
appraised from numerous well sites located
around the world. Goldberg & Saito comment
on the results of downhole logging on the ODP
Blake Ridge sites, standing up for 'loggingwhile-drilling' in hydrate investigations.
In general, geophysics has the potential to
achieve more than it has to date. While significant research is still needed to understand the
true physical nature of the BSR (the 'bottom
simulating reflector'), it is necessary to treat it
on its own merits and, through the above calibrations and a move towards more high-resolution
seismics, further focus on the most significant
sedimentary section, which stretches from the
BSR to the seabed.
Both Hobro et al. and Tinivella et al. demonstrate the power of seismic tomographic inversion studies for elucidating the velocity
distribution above BSR horizons. Mienert et al.
discuss high-resolution results obtained from
ocean bottom seismometers and from modelling
using trial and error ray tracing.
But how far can we go with ground-truthing?
The exploration phase for oceanic hydrates is
in its early stages. We are still seeking to identify
3
the physical criteria which will allow mapping of
hydrate reservoirs: 'BSR'-mapping is still the
only, and debatable, strategy. There is an
urgent need for ample drilling efforts and adequate sample recovery. In most cases targets
will call for three-dimensional approaches. However, drilling is expensive, so a strategy is needed
and site selection criteria have to be identified.
Ground-truthing should focus on end members
and type localities which span a wide spectrum
of hydrate habitats. Research should proceed
until each end member, in each type of hydrate
accumulation, is categorized.
There was a consensus in the workshop
debates that sites for investigation should ideally
be selected where seeps are observed, and that
such seeps need to be quantified, and qualified.
This calls for monitoring of fluxes and for
sample collection and in situ chemical analyses.
It is important to assess how much gas is seeping
from hydrate zones and non-hydrate zones, from
focused vents and diffuse venting areas. How
much is released as a steady state flow, and
how much as episodic venting, inasmuch as the
latter can be evaluated during times available
for observation.
We need fresh observations of modern venting
systems in order to try to understand their
dynamics. We can only issue warnings today
about trends in CO2 levels in the atmosphere
because of decades of observation. The basic
technology is available, and improvements of
instruments are straightforward. Even low-cost,
long-term thermistor stations can teach us how
temperature drives the system. If we are truly
convinced that the issue is scientifically important, we must start monitoring stations in the
deep sea. Over a time scale of a few decades,
especially in areas prone to slope instabilities,
an event will eventually happen that we will be
able to record.
Major gas hydrate occurrences: case studies
A second debate at the workship ventured to
target areas where international and multi-disciplinary research efforts, over a sustained period,
may shed light on significant oceanic gas hydrate
occurrences and quantify the elements needed for
both resource assessment and climatic modelling.
Contributors to the debate were Bill Dillon and
Michael Ivanov (panel members), Jiirgen Mienert (moderator), Mike Baillie, Angelo Camerlenghi, Gabriel Ginsburg, Myriam Kastner,
Bilal Haq, Mike Helgerud, Jean-Pierre Henriet,
Charles Paull, Dominique Raynaud, Carolyn
Ruppel, Dendy Sloan and Warren Wood.
4
J.-P. HENRIET & J. MIENERT
Introducing the evaluation of potential target
areas raised the issue of gaps in our approaches:
both topical gaps and scale gaps. We have
already come a long way in bridging topical
gaps, in particular between geophysical research
and geochemical investigations, which have
dominated the scene so far, by the study of
chemical gradients over large sections, laboratory studies, well logging and thermal studies.
But we still have scale gaps. Somewhere between
the scale of molecules and logging scales we
already seem to have a problem. What is going
on within the pores? What is going on at a
scale of centimetres to metres? This is where
much more research involvement is required.
Such involvement will primarily require field
exploration and experiments, initially using
downhole experiments. We need to look at
hydrates even before they are brought up the
hole. For such purposes some field study sites
should be set up and agreed upon by a wide
research community. Places where high concentrations of gas hydrates are found and where
the geological background is already well documented should be used for such experiments.
Still on the question of scales, but at the other
end of the spectrum: as we move towards analysing the possible coupling between ocean and
seabed through bottom currents, the transmission of thermal pulses from a warming or cooling
atmosphere via the hydrosphere to the seabed
and the resulting decay or growth of oceanic
hydrates, the responses of slopes through giant
slides or sequences of slides, we analyse basinwide phenomena. The logical scale for studying
the climatic role of hydrates and for making the
link with thermal models of the ocean will be
the oceanic basin, such as the North Atlantic,
or the Arctic. In a climate perspective, the
choice of study sites should also aim to clarify
the behaviour at the basin scale.
In the Atlantic, following ODP Leg 164, the
Blake Ridge is probably one of the best known
hydrate areas. Paull et al. and Thiery et al.
report on the preliminary field data and some
most interesting geochemical analyses of pore
fluids. New ideas will be developed from the
research that has been done so far and this is a
sound reason for re-visiting these sites to check
these ideas, to validate the models on the holes
and to continue research, with high-resolution
geophysics on the well sites and with a possible
move towards in situ experimenting and monitoring. But for research within the context of European programmes, more proximal target areas
will have to be identified.
Europe's Mediterranean flank and, in particular, the eastern Mediterranean and the Black Sea,
offer attractive perspectives though specifically in
relation to the geodynamic setting of convergent
margins and to the particular oceanographic
environment of confined seas. The association
of seeps with mud volcanism and H2S degassing
is important, while there is an ample background
database including multibeam, single- and multichannel seismic data. The Black Sea offers the
possibility of a transect from the deep-sea to
the shelf and even to the land, and the chance
to observe a whole range of degassing processes
and the distribution of hydrates as a function
of water depth. Shallow and relatively nearshore sites would allow cost-effective re-sampling
and monitoring.
De Lange & Brumsack report on gas hydrates
from mud domes in the eastern Mediterranean
and present what is probably the first estimate
of the total amount of shallow methane associated with mud dome structures on the eastern
Mediterranean Ridge. Their results, seen against
a background of the recently discovered fast rise
in bottom-water temperature in the Mediterranean, have a particular significance. Woodside
et al. describe gas hydrates and mud volcanoes
associated with the Anaximander Mountains offshore southwest Turkey, in the vicinity of
recently discovered giant mass movements such
as the Great Slide in the eastern Mediterranean.
Deep fluid fluxes and hydrate accumulations
associated with authigenic carbonates and bacterial mats are reported by Ivanov et al. and Bouriak & Akhmetjanov on the Crimean continental
margin in the Black Sea.
The degassing potential of the eastern Mediterranean and the Black Sea brought human
development into focus at the Gent workshop.
The eastern Mediterranean, being the cradle of
our literate civilisation, has generated a 5000year long human record, which, on at least one
occasion, underwent total collapse. Without
directly suggesting a causal link, we should bear
in mind that gas release, especially when toxic
gases like H2S are implied, may constitute a significant hazard.
If, however, we are looking for recent significant hydrate destabilization and seabed degassing
related to temperature rise, we should probably
focus on Europe's northernmost facade, the
Arctic Seas. Deglaciation caused the sudden
flooding of vast areas of Arctic shelves by water
that was 30°C warmer than the formerly exposed
substratum. If there is any place in the world
where hydrate breakdown should have manifested itself, it should be in the high-latitude
shelf seas.
Though Long et al. do not directly address the
former issue, which was raised in the debate at
GAS HYDRATES: THE GENT DEBATES
the workshop, their observations in the Barents
Sea still suggest that the present-day decay of
hydrates near large sea-floor craters supplies
widespread methane plumes which fluctuate in
response to seasonal warming of the bottom
water. Later in this book Mienert et al. interpret
similar observations differently.
Authors like Veerayya et al., Neben et al. and
Delisle et al. remind us of the significant hydrate
potential of Indian and southeast Asian continental margins. The last paper models the recovery of a BSR after a thermal disturbance at the
sea floor due to slumping, for instance. Such
modelling seems to show that the repositioning
of a BSR is a very slow process, taking place
over thousands of years.
There was a consensus in the conclusions of
the workshop debate that focusing on a few
areas with a multidisciplinary approach is an
essential objective. The selection of such areas
however requires more preparation.
Relevance to margin stability and climatic
change: research horizons
Delisle et al.'s exercise in the recovery of a thermal equilibrium in hydrate stability zones following a major disturbance of the seabed indirectly
links with what certainly turned out to be the
most stimulating and 'debatable' issue of the
Gent workshop, i.e. the possible coupling of
oceanic gas hydrates, margin instabilities and climate. This brought scientists from different
backgrounds into direct discussion. The direct
confrontation of ideas between atmospheric
modellers and ice core scientists on one side and
hydrate geochemists and geophysicists on the
other side turned into a captivating experience,
which left both parties with a taste for more.
Participants in this debate were Charles Paull,
Dominique Raynaud and Robert Thorpe (panel
members), Dendy Sloan (moderator), Hans
Amann, Lars Berge, Angelo Camerlenghi, Bill
Dillon, Bilal Haq, Myriam Kastner, Peter Kennett, Tom McGee, Walther Van Kesteren and
Warren Wood.
It is widely recognized that the present-day,
steady-state methane release from the ocean,
including from oceanic hydrates, is not impressive and that much larger releases, which could
affect climate, call for dramatic events such as
giant slides which, by one mechanism or another
may find their origin in the decay of hydrate horizons on the continental slope. It is already
known, through extensive acoustic mapping,
that vast stretches of the oceanic margins, in par-
5
ticular the North Atlantic, show evidence of
major large-scale slides and slumps.
The basic mechanisms through which decaying hydrates may affect the stability of slopes
are still poorly understood. Overpressure in the
pores below a decaying hydrate base may
account for a decrease in shear strength, but no
experimental evidence for any overpressure
under BSR horizons has been put forward to
date. Any build-up of overpressure will depend
upon the balance between hydrate decay and
pressure dissipation through possible permeability barriers. Furthermore, and by analogy with
the rationale behind the analysis of the generation of hydrates, we should not regard a slope
sediment as a simple, passive matrix, in particular not along formerly glaciated margins. The
nature of the clays significantly controls the stability of the sediments, and for some clays in particular the stability of the particle matrix is
directly controlled by the sodium content of the
pore water. Any freshening of the pore water,
e.g. by hydrate decay, may decrease the sodium
concentration and hence trigger slope instabilities through a possible 'quick clay' behaviour.
The most dramatic examples of quick clay
surges which have been documented occur in glacial sediments of the Scandinavian and Canadian
coastal plains and valleys which were deposited
in submarine environments and subsequently
uplifted and then leached by freshwater infiltration.
Mienert et al. demonstrate that deep-water gas
hydrate horizons are coincident with areas and
depths of slope failures in continental margin
sediments along the north-eastern Atlantic
margin, in particular in the Storegga slide area.
While across the Atlantic, in the Blake Ridge
hydrate province, faulted and collapsed depressions clearly seem to root at the base of the
hydrate stability zone and are interpreted by
Dillon et al. in terms of overpressure of gassy sediments just below the zone of hydrate stability.
Another process which needs clarification is
the fate of steady fluxes of methane from hydrate
reservoirs to the seabed and from the seabed to
the sea surface and atmosphere. We need to
understand the process of transport of gas
across geochemically active horizons like the sulphate reduction zone. And beyond the seabed,
what is the fate of methane in the water
column, as a function of discharge rate, bubble
size and dynamics? Do we fully master the chemical kinetics, and have we a feeling of how much is
subject to oxidation and take-up by the biosphere on the way to the surface? The absence
of experts in this field was seen to represent a
knowledge gap at the workshop.
6
J.-P. HENRIET & J. MIENERT
If any significant slide-induced flux of methane
from the ocean to the atmosphere is substantiated, the next step is to attempt to calculate
and model the radiative forcing of potentially
large and sudden releases of methane on climate
change.
It is clear that we need to understand the relative sensitivity of the whole environment in
which clathrates occur and decay, in which
methane migrates, and the relative sensitivity
through time. We have evidence of rapid major
climate changes in the Quaternary and there is
no answer so far as to what is forcing these
rapid changes. We have evidence of major slide
events in the Quaternary, and suspect a significant coupling, but have no real clues yet. But as
the past is the key to the future, we have to scrutinize long-term records of slope instabilities and
fast climate changes to gather such data.
Haq reviews the possible coupling mechanisms
between seabed degassing and climatic changes
and screens possible long-term climatic and
slope-stability records. Stable isotope records
suggest the Late Paleocene - Early Eocene
warming peak may be a past analogy, which
could offer further clues about the behaviour of
gas hydrates and their contribution to global
warming. He also digs into the more remote
past, towards 'pre-psychrospheric' times.
A study of the stable isotope record of the
Santa Barbara Basin off California (an oral communication by Peter Kennett et al. at the Gent
workshop) based on recently drilled ODP holes
has revealed rapid warming events which can
be explained by seabed degassing, and that
seem to be synchronous with warmings associated with Dansgaard-Oeschger events recorded
in Greenland ice cores. One reason why clathrates have so far not emerged as a dynamic component of the climate machine is that for a long
time there has been a sense that the deep seas
beyond the continental shelves were relatively
stable in terms of hydrographic conditions. One
of the results coming out of ODP and in particular from the Santa Barbara data is that this is not
true. At least in the Northwest Pacific, physical
oceanographic conditions have been very
unstable in Quaternary times, with bottomwater temperatures varying up to 3°C, which is
very significant in terms of hydrate stability.
Hydrates can thus be produced and released in
a pumping type mechanism, that could affect
global climate change. However the global relevance of results from one basin must be treated
with caution until they can be substantiated by
further data.
As emphasized by the climatologists and icecore scientists at the workshop, what turns out
to be a priority now, certainly if we are aiming
to model a possible coupling between seabed
and atmosphere, is the need to refine the sampling resolution and hence the time resolution
in all these records and thus allow reliable correlations and identification of lead and lag mechanisms.
Thorpe et al. model a 'Catastrophic Hydrate
Release' (CHR) of methane at the termination
of the last glaciation as indicated by ice core
results to test its potential impact on glacial climate. They come to the conclusion that methane
alone could not trigger deglaciation. However, a
combination of methane release, increase in
carbon dioxide and changes in heat transport
by the ocean - coupled with high climate sensitivity - could simulate changes of the observed
magnitude. Raynaud et al. also confirm that present evidence from ice cores does not show evidence for CHR, but the resolution of the ice
record is not refined enough to unequivocally
resolve leads and lags between methane and
carbon dioxide surges and temperature rises.
According to Thorpe et al., if the GRIP core
sampling interval could be reduced to allow a
resolution of around 50 years, then it would be
possible to more fully test the CHR hypothesis.
Still a major issue for the climatic relevance of
the world hydrate reservoir is the validation of its
size, at a global scale. We will never achieve accurate estimates, but we need meaningful estimates.
Can the Blake Ridge results be regarded as representative of other rich hydrate provinces, or is it
an exception? This question leads us back to the
exploration and ground-truthing debate, which
is most significant for the estimation of the relevance of oceanic hydrates for the Earth's climate.
Beyond these scientific arguments, the climate
debate has profound human dimensions of culture, communication and strategic priorities. As
suggested by a climate modeller at the workshop,
we might wonder why the climate modelling
community has traditionally paid so little attention to the significance of gas hydrates, though
there is increasing evidence of their huge potential. One reason is that the climate community
is presently deeply concerned with trying to
understand what is going on now and what is
going to happen in the near future, and what
we might be about to do to the climate system
other than what we are doing at this time.
It is a matter of economic pressure, of population growth, of how much energy resources are
going to be used, of how much CO2 will be
emitted. In this process, uncertainties are large
- about emissions, about climate sensitivity,
about the climate response to forcing by greenhouse gases - and it is generally felt that these
GAS HYDRATES: THE GENT DEBATES
uncertainties coupled together are very much
greater than the potential uncertainties associated
with the possible release of clathrate gases in the
future. That is, to a large extent, why clathrate
research has traditionally had a low profile.
Which strategy for international
cooperation?
The final Gent debate focused on defining strategies for international and multidisciplinary
research efforts. Participants were Jean Boissonnas (EC MAST), Bilal Haq and R. Heinrichs
(NSF), Laurent d'Ozouville (EMaPS) (panel
members), Jean-Pierre Henriet (moderator),
Ray Cranston, Jean-Paul Foucher, Myriam
Kastner, Jim Kennett, Tom McGee, Dominique
Raynaud, John Roberts, Carolyn Ruppel and M.
Veerayya.
The challenge of unveiling the possible coupling of the seabed and climate through gas
hydrates is a topic of global cooperation across
discipline boundaries. Over the next decade, the
Ocean Drilling Program will include a significant
component looking at gas hydrates, with one or
more focused legs, but it is resource-limited.
Other organizations are needed, other science
structures that will enable the scientific community to get at the fully multidisciplinary and interdisciplinary nature of clathrates. The possible
input of a Japanese drilling ship, currently at
the planning stage, might broaden the scientific
perspectives for hydrate research.
For the European Union, the Gent workshop
coincided with the drafting of the 5th Framework Programme (5th FP) which will significantly differ in its structure and objectives from
the previous programmes. Emphasis will be laid
on industry-driven research, research that more
closely answers the needs of society, and research
on the environment and the resources of the
living world. Clathrate research could fit into
such schemes, provided scientists can convey
the proper messages to their national authorities
as the 5th FP is finalized.
But whatever the prospects may be, European
Union support would necessarily focus on
European margins. These include the Mediterranean Sea, and possibly the Black Sea. However,
such priorities do not preclude international
agreements, and talks have been opened with
the US Administration to draft an official agreement which includes matters relating to marine
science and technology. At present teams from
the US, Canada and Australia can join EU
teams on a project provided they bring their
own funding. Cooperation schemes with Russian
7
partners also exist and will be developed.
Regarding cooperation with a country with
advanced clathrate research like Japan, farstretching bilateral agreements are already in
place with the US and Canada respectively
which focus on Pacific basins research and matters of technology. However cooperation with
other partners, in particular along the Indian
Ocean margins and in southwest Asian regions,
should not be overlooked.
Still on the European scene, the European
Board for Marine and Polar Science (EMaPS)
has promoted communication (networking)
among scientists and the case for a European
strategy for ocean drilling, involving a new
synergy with industrial partners. Two workshops
have already been organized, one on scientific
strategies in Europe for ocean drilling, including
ODP and programmes like CORSAIRES or
IMAGES, and another to identify new technologies for scientific drilling.
In terms of programmes, attention should also
be paid to the US MARGIN initiative, on its way
to becoming internationalized. The British and
French continental margins communities have
recently started their own programme. Such programmes include fluid flow as a broad general
topic and encompass clathrate research.
Throughout these programmes, technology
development for exploration, for ground-truthing and for monitoring needs to be a focal
point. Communication of data is also important,
as is sharing of equipment to collect new data. It
is the conveners' hope that the Gent workshop
and its debates will contribute to these objectives.
The Gent workshop 'Gas Hydrates: Relevance to
World Margin Stability and Climatic Change' was supported by the EC MAST 3 Concerted Action CORSAIRES. Behind the convenors' names, a large team
contributed to the success of the workshop and the editing of this volume. Special credit goes to Tine Missiaen,
Maarten Vanneste, Marc De Batist, Marc Faure
Didelle and Dries Declercq. Alister Skinner and Dan
Evans from the British Geological Survey are gratefully
acknowledged for a careful reading of this manuscript.
Professor Robert Kidd
Professor Robert Kidd was keen to be among the
participants of the workshop 'Gas Hydrates:
Relevance to World Margin Stability and Climatic Change'. Relevant work he intended to
propose dealt with sediment instability on the
margin of the Canaries, as part of the EC
MAST2 'STEAM' project, and with methane
driven mud volcano extrusion on the Mediterranean Ridge, as part of TREDMAR. He also
8
J.-P. HENRIET & J. MIENERT
planned a more general talk on JOIDES' interest
in gas hydrates, based on ODP's Long Range
Plan: a topic he already had brilliantly presented
in front of the EMaPS Marine Board in Rotter-
dam, on 9 May 1996. Tragically, Rob passed
away a few weeks later, in early June, aged 48.
His manifold contributions to marine sciences
will be sadly missed.